Candesartan Amlodipine Segmented Granulate Stability
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Solution Overview
Problem
The preparation of combination pharmaceutical compositions of candesartan cilexetil and amlodipine poses challenges due to stability issues, low bioavailability, and susceptibility to degradation, particularly with existing excipients like polyethylene glycol and lactose, which affect the uniformity and bioequivalence of the active ingredients.
Innovation Solution
A combination pharmaceutical composition is formulated as a uniform solid blend with candesartan cilexetil and amlodipine or its salt, using a granulate comprising polyethylene glycol and excipients like fillers, disintegrants, and binders, along with an extragranular phase containing amlodipine and its excipients, to maintain stability and bioavailability, avoiding direct contact with degrading agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If candesartan cilexetil and amlodipine are combined in a single pharmaceutical composition, then the therapeutic efficacy against hypertension is improved and treatment compliance is increased, but the stability of the composition deteriorates due to degradation of active substances
Solution Approach 1:
The composition is segmented into two distinct phases: a granulate phase containing candesartan cilexetil with polyethylene glycol and excipients, and an extragranular phase containing amlodipine with different excipients. This segmentation prevents direct contact between incompatible substances while maintaining them in a single dosage form, thereby improving stability without compromising therapeutic efficacy.
Solution Approach 2:
Amlodipine is extracted from the granulate matrix and placed in a separate extragranular phase. This extraction removes amlodipine from the degrading environment created by polyethylene glycol and lactose in the granulate, preventing its degradation while maintaining the beneficial effects of the combination therapy.
2Reliability
If polyethylene glycol is used as a stabilizing excipient for candesartan cilexetil, then the bioavailability of candesartan is improved, but the stability of amlodipine deteriorates due to incompatibility and degradation
Solution Approach 1:
The composition is divided into a granulate phase containing polyethylene glycol and candesartan cilexetil, and an extragranular phase containing amlodipine. This segmentation allows polyethylene glycol to stabilize and enhance candesartan bioavailability within the granulate while preventing its contact with amlodipine, thereby maintaining amlodipine stability.
Solution Approach 2:
Amlodipine is taken out from the granulate phase and placed in a separate extragranular phase, removing it from the polyethylene glycol environment that causes its degradation. This extraction preserves amlodipine stability while allowing polyethylene glycol to continue functioning as a stabilizer for candesartan in the granulate phase.
3Ease of manufacture
If a uniform mixture of candesartan cilexetil and amlodipine is prepared, then the manufacturing process is simplified, but the content uniformity deteriorates due to poor flow properties and static electricity
Solution Approach 1:
The composition is prepared as a mixture of granulate and extragranular phases rather than a completely uniform mixture. This segmented approach maintains manufacturing simplicity while improving content uniformity, as each phase can be optimized for its specific properties (granulate for flow, extragranular for distribution) before final combination.
Solution Approach 2:
Different regions of the composition have different properties: the granulate phase has optimized flow properties for handling, while the extragranular phase provides uniform distribution of amlodipine. This local differentiation of qualities resolves the contradiction between manufacturing ease and content uniformity.
4Ease of operation
If the dosage form size is reduced to improve patient compliance, then the convenience of administration is improved, but the stability deteriorates due to increased surface area exposure to degrading factors
Solution Approach 1:
The composition is segmented into granulate and extragranular phases, creating a structured internal architecture that protects active substances from degradation. This segmentation allows for compact dosage form design with improved patient compliance while the phase separation maintains stability by preventing contact between incompatible substances, even at reduced sizes.
Data Source
AI summary
A combination pharmaceutical composition comprising candesartan cilexetil and amiodipine or a pharmaceutically acceptable salt thereof, a process for the preparation of such composition and unit dosage form comprising such a composition. The composition consists of a granulate containing candesartan cilexetil, polyethylene glycol and other excipients, wherein the weight ratio of candesartan cilexetil to polyethylene glycol is in the range from 5: 1 to 2: 1, and extragranular phase of powder blend comprising amiodipine or a pharmaceutically acceptable salt thereof and excipients. The composition is prepared by mixing the granulate prepared by wet granulation and extragranular phase.